BG244 is good stuff. Wynns produces a variety of diesel additives (get the black bottle pro ones, not the purple bottle consumer ones), many of which use a cerium compound to lower the temperature at which accumulated soot ignites. Strangely this exactly the same chemical compound found in Rhodia's (formerly Rhone-Poulenc) Eolys! I have a suspicion that Wynns Diesel Power 3, Diesel Clean 3 and DPF regenerator are all exactly the same but marketed as separate products to increase the appeal of the product and maximise sales.
Two stroke oil is a good additive to use with diesel fuel, 1:200 dilution in the tank when refuelling. You must use low ash 2T oil, and you must avoid fully synthetic ones.
Avoid supermarket diesel.
I have a liking for BP Ultimate. This suits the Passat nicely. The PD engines (esp the 16 valve ones) are a bit 'industrial' in nature and BP Ult does calm down the combustion noise a bit. 2 stroke oil is also very very good at reducing engine noise.
I also used BP Ult in the 2.2 HDi Peugeot and found it to be an excellent fuel.
I fling Wynns DPF cleaner though my non-DPF periodically to help shift accumulated crud on the turbo vanes. Not that it gets much chance to accrue crud, I do drive it sensibly ie. not changing up stupidly early and not lingering in high gears. Plus most of my journeys are on open roads, always a good thing.
Most diesel cars are bought for economy but ironically the best way to keep the engine performing at its best, and most economically, is to drive in such a manner that is not automatically conducive to best fuel economy!!
